Let me break this down for you since arrow crafting can be a bit tricky to understand at first. You absolutely need arrowheads to make functional arrows (this is because the game simulates realistic hunting mechanics), but there are actually two ways to get them. The first method is heading to a forge, like the one in the riken ship or forlorn muskeg, where you'll need some scrap metal, a heavy hammer, and about 5-8 pieces of coal (make sure the forge is heated above 150°c before starting).

The other approach, which is pretty interesting, involves salvaging broken arrows you might find while exploring (places like carter hydro dam usually have a couple). You'll still need to gather cured birch saplings for the shafts and collect feathers from animal carcasses, but that's the easier part. The tricky part about arrowheads is that they're a finite resource unless you make the journey to a forge, which is why many experienced survivors plan their forge runs carefully (might be worth stocking up when you're there).

Something worth noting is that even though it might seem logical to craft primitive arrows with sharpened wood or stone tips, the game doesn't allow for this kind of improvisation. This design choice actually makes arrow crafting one of the more challenging aspects of long-term survival, but that's part of what makes the whole experience feel more authentic.